1.Combine cornflour, soy sauce, vinegar, eggwhite and half of wine in a medium bowl. Add chicken and stir to coat. Cover with plastic wrap and refrigerate for 15 mins to marinate.
2.Heat half of rice bran oil and half of sesame oil, if using, in a wok or large frying pan on high. Stir-fry chicken in two batches for 2 mins, until opaque. Remove from pan.
3.Heat remaining oils in same pan on medium. Stir-fry cashews and garlic for 30 secs, until lightly browned. Don’t let garlic burn. Add pak choy and stir-fry for 30 secs, until wilted.
4.Return chicken to wok with remaining wine. Increase heat to high. Stir-fry for 1 min, until chicken is cooked and juices thicken slightly. Top with green onion and serve with rice.